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Old 05-13-2006, 05:02 AM   #26
bugeyes
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Lots of money for little gain!
I had a personal discussion with Rigoli regarding heads when I was building my current engine. His advice came down a single line of recommendation-
"use sti version 5/6 heads (pre avcs), they have large ports. Give them a service and clean and throw them on with sti ver 5 cams. We have guys running 10's with them"
That was straight from the man.
When I asked about oversized valves and porting he said "dont bother".
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Old 05-13-2006, 10:06 PM   #27
PeteDucati
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I don't know much - but I do know ported Subaru heads flow around the same as some heavily ported eight cylinder SB Chevy heads. Considering we're aiming for eight cylinder power with a motor half the size I'm gonna disagree with Rigoli. And what constitutes "Lots of money for little gain!" Some have claimed 30whp gains with just head work - and no one has really done any clear tests regarding cam shafts.
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Old 05-15-2006, 09:46 PM   #28
djviper
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Quote:
Originally Posted by bugeyes
Lots of money for little gain!
I had a personal discussion with Rigoli regarding heads when I was building my current engine. His advice came down a single line of recommendation-
"use sti version 5/6 heads (pre avcs), they have large ports. Give them a service and clean and throw them on with sti ver 5 cams. We have guys running 10's with them"
That was straight from the man.
When I asked about oversized valves and porting he said "dont bother".
so on the basis of one mans word your going to dis miss the advice and expertiese of everyone else?! it is widly regarded that scooby heads need work to flow above 400whp, yes you can hit 10's on a cleaned up head but youll be over working the turbo, that means its working harder for less!
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Old 05-16-2006, 03:15 AM   #29
Uwish
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Guys, Rigolis ( TRP ) have the fastest rex in the world.
8.3 is a very good reason to listen to the man.

They know there ****!

I have also been told the same thing.
Thats why Im weighing up what do do with my V8 STI AVCS heads I have sitting on the garage floor

Damn subbies!
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Old 05-16-2006, 09:40 AM   #30
n2xlr8n
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It lives! ; )

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Quote:
Originally Posted by Uwish
8.3 is a very good reason to listen to the man.

Exactly.

Listen to the misinformationet gurus, not the guys out there wrenching on the fast cars

Both myself and Nathan from TXS (nmyeti) posted a looooong time ago that the stock WRX heads flowed well enough for >500hp.....but the camshafts need to be replaced to support that.

S.
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Old 05-16-2006, 09:44 AM   #31
BALISTC
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Quote:
Originally Posted by Hopper
When you cut your valves and seats the valve will sink in the head, reducing the valve to bucket to cam clearance. The base circle on the crower with smaller base circle is at .025 smaller than stock.
My custom camshafts were a totally different base circle to the AVCS cams that came out of the complete STi heads that I bought, so I had the valve seats machined a bit, and stellite applied to the tips of the valves to extend them (ever so slightly, about 10 thousands of an inch), to set the clearances correctly.

I got the heads for really cheap, and doing the prep work on the valves and seats was cheaper than buying all new buckets to set the clearances correctly!

I also had the ports deburred and mildly ported, the splitters were knife edged too. They sit on top of a V7 Spec C EJ207.

The motor is still being run in. In combination with the cams, I've never felt so much bottom end torque from a 2 litre engine, even with the break-in tune in place!!

Last edited by BALISTC; 05-16-2006 at 09:50 AM.
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Old 05-16-2006, 10:06 AM   #32
Shabib67
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Off-topic anyone know how much crucial racing charges for head work? Second im thinking about buying v8 spec-c-ra heads and slapping them on to my ej257. What setup will make more power.

Stock Heads
Springs+Retainers+Shimless buckets
PnP + 3 angle valve job
DPR Stage 3 AVCS Cams

or

v8 Spec-c-ra heads
PnP+3 angle valve job
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Old 05-16-2006, 02:49 PM   #33
djviper
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Quote:
Originally Posted by n2xlr8n
Exactly.

Listen to the misinformationet gurus, not the guys out there wrenching on the fast cars

Both myself and Nathan from TXS (nmyeti) posted a looooong time ago that the stock WRX heads flowed well enough for >500hp.....but the camshafts need to be replaced to support that.

S.
so 500 crankhp or 400 whp then?!!
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Old 05-16-2006, 03:47 PM   #34
InfamousDX
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Quote:
Originally Posted by Shabib67
Off-topic anyone know how much crucial racing charges for head work? Second im thinking about buying v8 spec-c-ra heads and slapping them on to my ej257. What setup will make more power.

Stock Heads
Springs+Retainers+Shimless buckets
PnP + 3 angle valve job
DPR Stage 3 AVCS Cams

or

v8 Spec-c-ra heads
PnP+3 angle valve job
They have prices in their original vendor for sale thread about coatings and headwork. Or email them because Jeremy is quick like a fox.
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Old 05-16-2006, 06:59 PM   #35
Hopper
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Quote:
Originally Posted by BALISTC
My custom camshafts were a totally different base circle to the AVCS cams that came out of the complete STi heads that I bought, so I had the valve seats machined a bit, and stellite applied to the tips of the valves to extend them (ever so slightly, about 10 thousands of an inch), to set the clearances correctly.

I got the heads for really cheap, and doing the prep work on the valves and seats was cheaper than buying all new buckets to set the clearances correctly!

I also had the ports deburred and mildly ported, the splitters were knife edged too. They sit on top of a V7 Spec C EJ207.

The motor is still being run in. In combination with the cams, I've never felt so much bottom end torque from a 2 litre engine, even with the break-in tune in place!!
If sinking the valves is too much you can install lash caps, or if your just installing regrind cams you can use the lash caps.

Iím glad to hear that youíre set up is working, keep us informed, maybe even a dyno pull with your boost graphed on the dyno sheet.
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Old 05-16-2006, 08:32 PM   #36
BALISTC
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M800, TD06, EJ207

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I suppose lash caps were an option, but it wasnt too hard to put .01 of an inch of stellite on the tips of the valves whilst the heads were apart

Do the lash caps just sit on top of the valves or are they "glued"? I dunno if I'd want to risk having those if they are just placed on top of the valves, I already broke a shim in the head running too much anti-lag, and I went shimless buckets so I wouldnt have the same problem again...ie, no bits to float around if the antilag held the valves open again!
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Old 05-16-2006, 09:45 PM   #37
burnin4
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I recently purchased a cobb stg2 block with a few upgrades (coated pistons, prof series bearings) as well as their stg2 head upgrade. I will be posting dyno results in 2 weeks. I look forward to seeing the benefits of a mild p&p.
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Old 05-16-2006, 09:49 PM   #38
700hp
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9.1 152mph

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Quote:
Originally Posted by Uwish
Guys, Rigolis ( TRP ) have the fastest rex in the world.
8.3 is a very good reason to listen to the man.

They know there ****!

I have also been told the same thing.
Thats why Im weighing up what do do with my V8 STI AVCS heads I have sitting on the garage floor

Damn subbies!
Yea, and i'll guarantee that the car you speak of that ran that time has extensive head work done to it. Its all about what you want to accomplish. My car made 678whp at 28psi with a 35r and this was only accomplished with extensive head work. I guarantee that at that same boost level with no head work it wouldn't have made over 600whp.
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Old 05-16-2006, 09:54 PM   #39
burnin4
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Quote:
Originally Posted by 700hp
Yea, and i'll guarantee that the car you speak of that ran that time has extensive head work done to it. Its all about what you want to accomplish. My car made 678whp at 28psi with a 35r and this was only accomplished with extensive head work. I guarantee that at that same boost level with no head work it wouldn't have made over 600whp.
do you think your cams had anything to do with the increased power?
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Old 05-16-2006, 10:00 PM   #40
700hp
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the car was never on the dyno before it had cams so i have no comparison #'s but Phil from Element tuned the car and he said that he has never seen a 2.5 with a 35r on put out so much power. He said that it had EVERYTHING to do with the heads.

This was my set-up if it does anything for you

272 cams
no AVCS
Jun adjustable cam gears
oversized Ferrea valves
Double Ferrea valve springs
Lots of porting
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Old 05-16-2006, 10:18 PM   #41
djviper
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Quote:
Originally Posted by burnin4
do you think your cams had anything to do with the increased power?
you can run the wildest cams, but if the heads cant flow the air theres no point!
interestingly 700 i was looking at the jun train, just trying to work out if there worth the rather tasty price!
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Old 05-16-2006, 10:25 PM   #42
kinger
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I'm going to try locally doing a set and try to post some data on before and after.
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Old 05-16-2006, 10:48 PM   #43
djviper
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http://forums.nasioc.com/forums/memb...oster&t=172110
ask andy! i think being in the top ten fastest he must know his shizzle
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Old 05-17-2006, 12:40 AM   #44
Jeremy@Cobb
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Quote:
Originally Posted by kinger
What part of the ports are ported using the CNC machine, how does the bit get in there? Specfically the hard bend the one exhaust port takes to exit near the first port. Thanks
I will take detailed pictures of the ports, when I get back from the Wicked Big Subaru Meet. You would be surprised what a 5 axis CNC can do along with the small bits.

Jeremy.
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Old 05-17-2006, 12:47 AM   #45
Jeremy@Cobb
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Quote:
Originally Posted by djviper
you can run the wildest cams, but if the heads cant flow the air theres no point!
interestingly 700 i was looking at the jun train, just trying to work out if there worth the rather tasty price!
You are exactly right.. looking at a flow chart you are comparing flow vs lift. On our subaru heads (unported or ported) after a certain lift, larger cams will not gain any power but gradually move the powerband towards the right.

-Jeremy.
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Old 05-17-2006, 01:33 AM   #46
Hopper
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Jeremy,
Would you mind posting your flow charts for a stock WRX head and your Ported CNC head? At what test pressure? Iíd like to see the difference, if you donít mind. Could you share your port volume and combustion chamber volume also?
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Old 05-17-2006, 01:40 AM   #47
djviper
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you dont expect much do you hooper! why not just ask for the technical disc for the cnc machine?
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Old 05-17-2006, 10:13 AM   #48
InfamousDX
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700hp... what heads did your worked ones start out as.. USDM STI?
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Old 05-17-2006, 11:06 AM   #49
Matt Monson
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Quote:
Originally Posted by djviper
you dont expect much do you hooper! why not just ask for the technical disc for the cnc machine?
Maybe they do it differently across the pond, but over here, most tuners are pretty open with their numbers on anything they are selling to the general public. And most customers get a copy of the bench flow numbers with their heads when they arrive. I know I did with mine. Now, if I were building a race engine, I may be wary to release my #'s, but on a stage I or stage II port job, it helps you sell product...


According to the numbers I have seen from Cobb, EJ205 heads, stock, flow around 245cfm intake and 170cfm exhaust at .4 lift, at 28", IIRC. These may be off by 5-10cfm because I am pulling off an old chart, but I am sure Jeremy will correct me if I am way off. I don't have after numbers, but at least that gives you a starting point...

And if you guys were paying attention to what Rigoli said, he was talking about using Ej207 v5 or v6 STi heads in stock form. These heads flow WAY better than the EJ205 heads. To get those kinds of numbers from Ej205 heads, you must port them.

Or, and I know that this is blasphemy around here, use DOHC NA Ej25 heads. They outflow Ej205 heads by about 10%, which is in the neighborhood of what a mild Ej205 port job will get you. Xephyr, and a handful of other people, have broken 400whp on those heads(with an Ej257 bottom end). It will require changing the manifold, and fuel rails, but anyone looking for those power levels is changing the rails anyways, and also likely using a front mount, so intake plumbing is a non-issue. It's very easy to tap the back of the heads for the oil and coolant since they are pretty much based on the Ej20K head castings, and just need to be milled out and tapped for threads. They already have the casting for the placement of those items. This is not to say they are the same heads, but they are based on them, and would be a viable low cost alternative to $1500+ worth of port work. And V3 HKS STi cams are a direct drop in...
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Old 05-17-2006, 05:08 PM   #50
burnin4
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Quote:
Originally Posted by Jeremy@Cobb
You are exactly right.. looking at a flow chart you are comparing flow vs lift. On our subaru heads (unported or ported) after a certain lift, larger cams will not gain any power but gradually move the powerband towards the right.

-Jeremy.
which cams would you suggest for the cobb stg2 block/stg2 head p&p?
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